Automotive USB charging head unit
The USB Charging module for the head unit application is also referred to as Break-out-Box (BoB) module. The module supports USB-C Power Delivery (max of 100 W) along with USB Data connectivity from a phone, to support Apple CarPlay or Android Auto, or a USB Storage Device to stream content. The BoB could also support a USB Hub to connect more than one USB Device to the Had Unit.
EZ-PD™ CCG7Sand EZ-PD™ CCG7D are, respectively, single- and dual-port USB PD controllers with integrated DC-DC buck-boost controllers. Based on an Arm® Cortex® processor with 128 KB Flash and GPIOs, they can interface with the USB hub over the I2C interface. Therefore, the head unit or Board Control Module (BCM) can interact with EZ-PD™ CCG7S/D via the USB hub and over the I2C interface. In order to do so, Infineon has developed a software interface protocol called Host Protocol Interface (HPI) to share the USB-PD port status with the head unit and BCM, and to control EZ-PD™ CCG7S/D’s functionality.
When connected to the head unit, EZ-PD™ CCG7S/D can receive OEM/Tier1 authenticated firmware Over-The-Air (via the LTE or Wi-Fi interfaces) or via the OBD port, it then uses Root of Trust Public Key (RoTPK), RSA-2048, and SHA-256 algorithms to validate the firmware before updating its internal Flash with the new firmware. This feature enables EZ-PD™ CCG7S/D to be up to date with the changing USB standards and any other firmware update that might be required for better functionality, even after the vehicle is out of the manufacturers´ production line.
EZ-PD™ CCG7S/D is the heart of the BoB, which integrates a 24 V LDO enabling the controller to be powered up from the automotive battery. The internal DC-DC buck-boost controllers drive the external dual H-bridge switching FETs. EZ-PD™ CCG7S/D integrates VCONN FETs to detect electronically marked USB Type-C cables that support 5A. It can accept up to 4 NTC thermistors to measure the temperature of the module, measurements that will be then used to throttle the output power.
- Dynamic load sharing between the USB-C ports
- I2C interface to USB Hub
- Output power throttling based on temperature and battery voltages
- Authenticated firmware update
- Black box feature to store a number of fault occurrences for diagnostics
- Support for Programmable Power Supply (optional spec of USB-C Power Delivery)
- VBATT to GND short protection